Finned evaporator



April '23, 1935. F. R. ERBACH 1,998;664

FINNED EVAPORATOR Filed July 10, 1933 Patented Apr. 23, 1935 UNITEDSTATES q 1,998,664 I y F1NND\ EVAPoRA'ron Fred R. Erbach, Beloit, Wis.,assgnor to General Refrigeration Corporation, Beloit,

poration of Delaware Wis., a cor- Application July 10, 1933, Serial No.679,647

Claims.

The invention relatesto heat exchanging apparatus and more particularlyto finned evaporators for refrigerating systems.

For increasing the heat absorbing surface of evaporators in order torealize the greatest possible heat transfer and maximum efficiency ofthe refrigerating system it has been .customary to provide the tubingwith exterior ns which may be described as washer-like discs having lllopenings therein for threading on the tubing and which are suitablysecured in spaced relation with each other. Proper construction ofthefinned evaporators requires that the ns be held together rinly toprovide a rigid unit preventing one n from becoming displaced withrespect vto an adjacent 1in and also that the fins have a secure unionwith the tubing for the greatest possible heat transfer.

An object of the invention is to provide a finned evaporator in whichthe discs assembled on the tubing are held in spaced relation by'meansintegral with the disc to eliminate the use of independent spacer platesvmailing a compact unit of rugged construction. means have contact withthe tubing and when spot-welded or galvanized to the tube serve toprovide a secure bond, holding the discs to the tubing in proper spacedrelation.

A more specic object of the invention resides in the provision of discshaving integral spacing prongs punched from the material of the centeropening therein and which are cf a length in excess of half thediameter-of the opening so as to space the discs a distance greater thanthe outside radius of the tube.-

A further object is to provide a disc for the purpose described havingspaced prongs punched from the material of the center opening thereinand which are substantially equal to the diameter of the opening.

A further 'object is to provide a disc having at least three spacingprongs integral therewith to make a three-point contact with an adjacentfin when assembled on the tube while spacing the fins a distance greaterthan the outside radius of the tube. This contact between a fin and thespacing prongs of an adjacent iin increases the rigidity of the assemblyand permits endwise pressure to be applied, holding the fins in tightrelationship preliminary to the bonding of the prongs to the tube.

With these and other objects in view, the invention may consist ofcertain novel features of construction and operation, as will be morefully described and particularly pointed out in the specification,drawing and claims appended hereto.

In the drawing which illustrates an embodiment of the device and whereinlike reference characters are used to designate like parts- The integralspacing Figure 1 is an elevational View showing a section of finnedtubing embodying the features of v'the invention;

disc of Figure 2 located on a section of tubing;

`Figure 4 is a plan View of a portion of a disc showing a modiedarrangement of the spacing prongs; t

Figure 5 is a vertical sectional view of the disc of Figure 4 with thespacing prongs bent at right angles to thedisc;

Figure 6 is a plan View of a portion of the disc showing still anothermodied arrangement of the spacing prongs; and v Figure '7 is anelevational view showing the disc if Figure 6 located on the section oftubing.

The section of finned tubing shown in Figure 1 comprises a length oftubing I0, of heat conducting material such as copper, brass or steel,having a plurality of Ifins or discs I2 also of heat conducting materialmounted thereon in spaced relation. The discs are provided with a centeropening of a diameter substantially equal to the outside diameter of thetubing and a plurality of spacing prongs so that the discs may beassembled on the tubing and maintained in spaced relation by the prongsengaging with the face of the next adjacent disc. As more clearlyillustrated in Figures-2 and 3 a preferred method of forming the prongsfrom the material of the center opening consists in punching openings I4in the material of the disc of the shape disclosed and which aresymmetrically positioned with respect to a horizontal and vertical linepassing throughthe center I5 of the disc. The material retained can bedescribed as extending diametrically of the center opening and issevered in accordance with the invention to provide the prong I6 and thebifurcated prong I8. The prongs are bent outwardly from the material ofthe disc at right angles thereto, as shown in Figure 3, to provide amulti-point support for retaining the discon the tubing with the face ofthe disc at substantially right angles to the periphery of the v tubing.Further contact between the disc and the tubing is provided by theflange 20 bent from the material of the disc and limited as to depth bythe extent of the recesses 22 located on the respective sides of thebase of each of the spacing prongs I6 and I8.

Forming the spacing prongs from the material of the center opening inthe disc provides integral prongs since the metal cornes from the discitself and which when severed according to the invention results inintegral spacing prongs having a length greater than the radius of thecenter opening. As the prongs are integral and lspacing plates withtheir additional cost are eliminated, securing greater economy in`manufacture, while improving the rigidity and compactness of theassembled unit. Also the length of the spacing prongs separates thediscs far enough apart for efficient operation while additionallyproviding a plurality or prongs for more effectively balancing the discon the tubing and for absorbing endwise pressure` to hold the parts intight relationship preliminary to the bonding of the prongs to thetubing.

In Figures 4 and 5 the punching of the center opening of the disc 30 ismodiiled to provide plurality of prongs, certain of which have a engthsubstantially equal to the ldiameter of he opening. This is effected bypunching open- /ings 32 of substantially semi-circular shapesymmetrically disposed with respect to vertical and horizontal linespassing through lthe center $4 of the disc. In blanking the openings 32material -is retained to form the tabs, The center strip extendingdiametrically of the openings is severed along the diameter to form thespacing prongs 38 which are trimmed at their ends 38 to provide a prongof the desired length. Prior to locating the disc 30 on a tube theprongs and tabs are bent at right angles to the disc, as shown in Figure5, providing a multi-point support for the disc by which the same may beheld in proper angular relation with the tube ,and which additionallyspaces the disc from an adjacent disc a distancel in excess of theradius of the tube but less than the diameter thereof.

In the modified structure of Figure 6 the opening formed in the disc 40is indicated by the dotted lines 42, all of the material ofthe openingbeing used in forming thev spacing prongs and securing nanges for thedisc. The material within the circle 42 is severed along line 44 to formthe spacing prongs 46 and the flanges 4I. When these members are bent atright angles to the disc, as shown in Figure 7, they form the centeropening therein and provide in effect a supporting sleeve, the spacingprongs 48 contacting the face of the next adjacent disc to space thesame a distance substantially equal to the diameter of the opening whilethe flanges 48 additionally engage the tubing merely for supportingpurposes.

The disc of Figure 2 in which the metal o! the center opening is blankedto form three spaced prongs exceeding in'length the radius of theopening has been found highly eiiicient in use due to the three-pointcontact which the circumferentially spaced prongs have with the iace ofthe next adjacent disc. Also the prongs serve to hold the ns rmly on thetube in proper angular position and in true alignment with those of theunit. For various installations, principally those which depend onnatural draft for circulating the air, it is desirable that the fins bespaced apart a distance which will not interfere with or hinder in anymanner the free flow of air between the fins. Accordingly, the iins ofthe invention have spacing prongs of a length greater than the radius ofthe opening as shown in Figure 2 and which may approximate or even equalthe diameter of the opening as in the modifications of Figures 4 and 6.It is entirely possible that spacing prongs equal to the radius of theopening will be satisfactory inra number of installations and theinvention is therefore to be considered as fulfilling this requirement,as the prongs can be `trimmed to this length and this applies to thedisc of Figure 2, wherein the prongs can be shortened without destroyingthe structural features of the invention.

It is to be understod that I do not wish to be limited by the exactembodiment of the device shown, which is merely by way of illustrationand not limitation, as various and other forms of the device will ofcourse be apparent to those skilled in the art without departing frm thespirit of the invention or the scope of the claims.

I claim: l

' 1. A disc for the'purposes described having a center opening thereinand prongs integral with the disc and extending from the disc atdiametrically opposite points around the opening, said prongs having alength in excess of the radius of 'thebpening and a bifurcated end onone of said prongs.

2. In a heat exchanger, the c '.mbination with a tubular member, ofdiscs carried by said member, each disc having a circular openingtherein through which the member extends, and prongs integral with thedisc and struck from the metal of said opening for spacing the discsfrom each other, said prongs having a length greater than the radius ofsaid opening and being spaced around the periphery of said tubularmember, certain of said prongs being Joined to the metal of the disc bycommon means.

y 3. In a heat exchanger, the combination with a tubular member, ofdiscs carried by said member, each disc having a circular openingtherein through which the member extends, and prongs integral with thedisc and struck from the metal of said opening for spacing the discsfrom eachv other, said prongs having a length greater than the radius ofthe opening, one of said prongs having a bifurcated end and said otherprongs being located diametrically opposite the space between the endsof said bifurcated prong. 4. In a heat exchanger, the combination wit atubular member, of discs carried by said member, each disc having acircular opening therein through which the member extends, and prongsintegral with the disc and struck from the metal of said opening forspacing the discs from each other, said prongs having a length greaterthan the radius of said opening, one of said prongs having a bifurcatedend forming a plurality of members spaced around the periphery of saidtubular member, and said other prongs having a width at its endsubstantially equal to the space between the ends of said bifurcatedprong and being located diametrically opposite said space.

5. In a heat exchanger, the combination with a tubular member, of discscarried by said member, each disc having a circular opening thereinthrough which the member extends, and prongs integral with the disc andstruck from the metal of said opening for spacing the discs from eachother, said prongs having a length greater than the radius of saidopening, one of said vprongs having a bifurcated end providing aplurality' of members spaced around `the periphery of said tubularmember, and a flange struck from the metal of said opening and engagingsaid tubular FRED R. ERBACH.

